Genomic DNA is extracted from saliva. Genotyping for the SLCO1B1*5 allele is performed using a PCR-based 5'-nuclease assay. Fluorescently labeled detection probes anneal to the target DNA. PCR is used to amplify the section of DNA that contains the *5 allele. If the detection probe is an exact match to the target DNA, the 5'-nuclease polymerase degrades the probe, the reporter dye is released from the effects of the quencher dye, and a fluorescent signal is detected. A genotype is assigned based on the allele-specific fluorescent signals that are detected.(Package insert: Taqman SNP Genotyping Assay, Applied Biosystems. rev D 07/2010)